1. Field of the Invention
The present invention relates to a charger for charging a cluster of secondary batteries or battery packs, and more particularly to a battery cluster charger having a plurality of charging circuits which is capable of replacing any failing charging circuit with another charging circuit to charge a battery pack.
2. Description of the Related Art
One conventional battery cluster charger is shown in FIG. 1 of the accompanying drawings. As shown in FIG. 1, the conventional battery cluster charger includes charging circuits 102, 103 corresponding respectively to secondary batteries or battery packs 104, 105. When an AC power supply 101 is switched on, the charging circuits 102, 103 start charging the battery packs 104, 105, respectively. When the battery packs 104, 105 are fully charged, the charging circuits 102, 103 complete their charging cycles.
Therefore, the conventional battery cluster charger comprises a plurality of independently operable charging circuits that correspond respectively to battery packs to be charged thereby.
If any one of the charging circuits suffers a failure, the failing charging circuit stops its charging operation, and the corresponding battery pack is not charged thereby. Some battery packs for business use are charged at night and used on the next day. If the charging circuit for charging one of such battery packs has failed and the battery pack has not been charged at night, then the uncharged condition of the battery is not recognized until the user actually attempts to use it. Consequently, the failure of any one of the charging circuits poses problems in the actual use of the battery packs.